What will happen to the pressure of a confined gas if the temperature of the gas is increased?

• A. The pressure will increase.
• B. The pressure will decrease.
• C. The pressure remains constant.
• D. The pressure becomes zero.

Answer: (A)

Raising the temperature of a gas confined to a fixed volume increases the pressure because the gas molecules move faster and collide with the container walls more vigorously. With the amount of gas and the volume unchanged, those faster, more frequent collisions translate into a greater force per unit area—the pressure rises. This follows PV = nRT, so at constant volume and amount (n and V fixed), pressure is proportional to the absolute temperature (in Kelvin). Thus heating the gas increases pressure. The other outcomes would require cooling, changing the volume to compensate, or the gas leaving or reaching absolute zero, none of which describe the given scenario.